It has been estimated that the income loss to U.S. producers from broken eggs is $266 million/year based on 240 million laying chickens. An additional loss of $211 million occurs due to uncollectable eggs at processing plants. Today, the U.S. has 338 million laying chickens, and egg loss due to breakage or uncollectable eggs could account for $375 million and $297 million/year, respectively. Global hen numbers are 6.6 billion and could account for losses due to breakage or uncollectable eggs of $7.3 billion and $5.8 billion respectively. With as much as 20% of the eggs lost from a given hen (300 egg/year), a total of $3.50 of an individual hen's production is lost due to egg breakage. The egg specific gravity, percent shell, and force to break the shell (grams of force) are negatively correlated with egg breakage in commercial egg production and packing facilities, with specific gravity and percent shell having a correlation coefficient of ≥0.85 (C. F. Strong, 1989, Poultry Science 68:1730-1733). A strategy that would reduce egg loss due to breakage would be of considerable value to egg producers.
There are no products that are currently marketed that consistently increase egg specific gravity, eggshell amount and force to break eggs (measures of “eggshell strength”) and thereby reduce egg breakage. For example, while calcium and vitamin D are two critical nutrients for assuring proper calcification of eggs, these nutrients are currently fed at levels that maximize eggshell strength. Sodium bicarbonate can restore shell strength caused by a depletion of blood bicarbonate when environmental temperatures are high such as in the summer, however, sodium bicarbonate does not actually increase shell strength per se.
What is needed are compositions and methods for reducing breakage and increasing eggshell strength in eggs laid by laying hens.